Method of gas production



April 2, 1929- w. ANDREWS ET AL METHOD OF GA'S PRODUCTION Filed May 20. 1922 I I I l I l I I I I n n Half/6.9 W 62262981115 Mama/z d Era @5672:

Patented Apr. 2, 1929 A crrARLEs w. ANDREWS. or DULUTH, MINNESOTA, AND HERMAN A. BRASSERT, or

1,707,651" UNITED STATES PATENTOFFICLQ CHICAGO, ILLINOIS.

METHOD or GAS PRODUCTION.

' Application filed May 20, 1922. Serial No. 562,337.

This invention relates to gas production and more particularly to a new and improved method for the continuous and complete gasification of'coal or similar fuels.

In the production of gas from coal, as now generally'carried out, the process of manufacture consists of two distinct steps. The first step involves the production of coke from the coal with the accompanying removal of gas, tar and ammonia. The second step involves the utilization of the coke so formed in manufacture of water-gas, which may ormay notbe carburetted;

In the presentpractice, the first or coking operation is carried on in an ordinary retort which may be horizontal, inclined or vertical, or in some type of coke oven. The resulting coke is always more or less cooled in transferring it to a water gas generator with resultant lossof heat. A'certain amount of the coke g'asified in gasproducers, is consumed in heating the retorts or coke ovens although in the latter case a corresponding amount of coke oven gas is generally used in place of coke.

The formation of Water-gas in the gas generator is accomplished by alternately blasting or forcing air through the coke to bring it to high temperature by means of comb-us tion and then passing steam through the highly heated coke. -During the air blasting operation, blast gases are formed which are sometimes used to heat waste-heat boilers. During this blasting, the combustion con sumes a large amount of coke in order to .compensate for the heat consumed in heating up the excess steam introduced during steaming.

During the steaming operation, bluewatergas is formed, the steam being broken down,

into hydrogenand oxygen, the latter uniting with the carbon of the coke to form carbon monoxide. If it is desired. to enrich this blue water-gas, it may be passed through a carbureter where oil 1s added and then the 7 oil and gas mixture may be passed through a erable heat losses due to the-removal of the coke from the retorts or coke ovens and the subsequent necessity of again raising its temperature in the gas generator. This process furthermore becomes costly on account of the expense inhandling the coke including the loss in breakage; also the broken'coke is not as efiicient in the generator as the larger size coke. A further considerable heat loss occurs due to the fact that the water-gas is formed at a relatively high temperature and that the sensible heat of the gas is not utilized.

The burning of an excess of coke during preliminary blasting and blasting between steaming causes high local temperatures which result in clinkering. This in turn recheckerwork and placed above a gas gencoking.

erator. In operation, fresh charges of coal are added periodically to the top of the retort. The air blastgases from the gas generator are passed through the checkerwork about the retort and serve to assist coking the coal therein. p

During the periods when steam is introduced for the formation of the water-gas, the outlet of the checker chamber is closed and the outlet at the top of the retort is opened. In this way, the blue water gas passes up through the retort and sweeps out the coal gas, and tar from the coal and completes the While this method offers a continuous process, it is, nevertheless, open to a number of objections. The efliciency is low owing to the fact that the heat of the blast gases is,

only partly utilized. Further, the production of ammonia. in thisprocess is very low.

An additional object lies in the fact that dur-.

ing the blasting period any gas, tar and ammonia which may be formed in the retort can only pass out by working down through the retort and going out with the blast gases.

Attempts have been made to producegas continuously and with complete gasification of the fuel in a single unit by continuous air blastingand steaming, but those systems necwater-gassets, but in this case the capacity has been greatly reduced, and in spite of the reduced rate of operation large quantities ,of coking coal are blown over which obstructs the passages, not to mention the loss in fuel, also far more steam is used than theoretically necessary on account of the channeling of the gases through the coal. This in previous methods .has only been overcome by having the 'coal carbonized in narrow retorts.

To overcome all of these difficulties we propose to reduce all of the coal to coke before air blasting by passing highly preheated blue water gas up through the mass of coal.

On account of carbonizing the coal in this manner we have a gas generator running on coke instead of coal when blasting and steam ing, doing away with all difiiculties of distribution in a coal operated gas generator.

The object of our invention'is to produce gas continuously in one system with com plete gasification of the fuel in the original unit without transfer of the coke or carbonaceous residue, and to produce gas substantially free'from nitrogen.

An additional object is to increase the thermal efficiency of the gas-making process compared to that of present commercial methods. We accomplish this by using highly superheated steam and preheated air in the generator of the water-gas, the temperature being such that both the steam and coke will be near the temperature of the water-gas reaction, thus materially accelerating the 'reaction. .This superheated steam and 'pre heated air is preferably introduced through tuyres laterally of the material and consequently a gas producer bottom may be used with the installation.

It is also an object to provide a process which utilizes the heat of the blast gases not utilized in the water-gas generator for pre heating the air and steam to increase correspondingl the temperature of the outgoing gases, bot blast and blue, whereby the temperature 'of the blue water gas will be ,sufliciently high to carbonize the fuel.

It is a further object to provide a process where the water-gas is heated after its genera tion, the latter heating being accomplished by assing the water-gas through a mass of eated coke. In the preferred cyclic operation, 7 this coke has remained heated from blasting in themakingl of water-gas in a.

' previous step of the eye It is an objectto provide a process wherein the sensible heat of the water-gas produced is utilized in the formation. of coke, and wherein the water-gas is further utilized to sweep out the coal gas andi'tar and ammonia from the coal.

It is a further object. to provide a process of this character wherein the water-gas is generated by passing steam upwardly through heated coke and whereby the hot water-gas is passed upwardly through a body of fuel to sweep the volatile contents therefrom. This passage of the hot gas upwardly through the fuel has the important result v that the gas passes from hotter to cooler regions of the fuel and consequently 'the volatile matter taken from the fuel is not passed through any temperatures above those at which that particular matter was volatilized. Thus none of the volatile matter is cracked after its liberation from the fuel.

' In its broad aspects our invention involves the use of sufficient units so that coal is constantly being coked and water-gas constantly being produced from coke. This permits a cyclic operation in such mannerthat each unit or each set of units serves in turn as a carbonizing chamber and then as a water-gas generator, both blasting and making gas.

We use units having relatively large crosssectional area for the fuel and coke and preferably provided with producer bottoms of the water-sealed automatic ash removal type. The air and steam are introduced through tuyeres at a point above the bottom and are preferably used under high temperatures. The tuyres and adjacent passages are suitably protected by fire brick or similar material. The water-gas is thus generated at a the coke. The coke has been heated by blast ing at the-expiration of a run during which the coke has been alternately steamed and air blasted to produce water-gas. As the heated gas passes upwardly through the layer of fuel, it loses a portion of its heat and carries gritlli it a portion of the volatile contents of the ue At the lower portion of the fuel layer where the gas enters it, the fuel has a relatively high temperature, and here those constituents which volatilize at relatively high temperatures are separated from the fuel. Further up in the body of the fuel the temperatures are lower and relatively low temperature distillation takes place. Since the gas is passed upwardly, the volatiles driven ofi at the lower temperatures do not pass through zones at higher temperature and are not cracked. The tendency with some coals would be for the gas to pass up through channels formed in the mass; or to pass up adjacent the walls of the unit. In order to prevent this, we may continually agitate the mass, for example, with ya coking a paratus of the type shown in the I is then passed through the heated coke in the fuel containing unit which materially increases its temperature so that there is a large amount of sensible heat available for carbonizing the fuel.

In a preferable mode of operation, stallation involves two or more units operated in a cycle whereby throughout the cycle, at least one unit acts as a carbonizing chamber and other units serve as water-gas generators, blasting and making gas in alternation, one or more at all times making gas, the sensible heat of which gas is utilized in the unit serving as a carbonizing chamber. The blasting is limited in amount and duration to the heat requirements of the gas-making process. 7 y

We have illustrated a preferred embodiment of our invention in the accompanying drawings, in which- Figure 1 is a somewhat diagrammatic plan view partly in section of an installation adapted for carrying out our process; and

Figure 2 is a vertical section taken on line 22 of Figure 1.

The units A and B are identical in construction. The unit A comprises an outer shell 5 and an interlining 6 of refractory material which serves to insulate and protect the shell. The unit'has a charging opening 7. protected by a cover 8 through which extends a poker 9 having a foot 10. This poker may be rotated or reciprocated by any suitable means (not,

shown) for the purpose of agitating or breaking up the mass of material in theunit. The intermediate portion of the unit is sloped inwardly at 11 to the reduced lower portion 12.

The lower end of the unit is closed by the' water-seal 13 and contains the cone bottom 14 provided with perforations 15. Air may be introduced through pipe 16 and steam through pipe 17, the air or steam passing up through the perforations 15. The lower reduced portion 12 of the unit is surrounded by the bustle pipe 18 which is connected to the unit by the tuyeres 19.. The bustle pipe and tuyeres are provided with a refractory lining as shown. 1 i

The upper end of unit A is connected by passage 20 with the bustle pipe 18 of ;unit' B, the passage 20 being controlled by valve 21. Similarly, the unit B has its upper portion connected by passage 22 withthe bustle pipe 18 of unit A, the passage 22 being .controlled by valve '23. The unit A is provided with the lead-oil passage 24 and unit isprovided with a similar passage 24..

As best shown in Figure 1, the passage 25 leads from the'upper portion of unit A to the carbureter K, this passage being controlled by v the invalve 26. Unit B is similarly connected to the carbureter by passage 27 controlled by valve 28. The carbureter K is connected by passage 29 controlled by valve 30 to the steam-heater L. The lead-off pipe 31 connects the bottom of the carbureter K with any suitable gas container (not shown).

The steam-heater L is connected to the- The StOVG Mis also provided with the exhaust passage 41 controlled by valve 42. The steamheater L is also connected by passage 43 controlled by valve 44 with the air stove O.- The stove O is provided with the exhaust passage 45 controlled by valve 46 and is connected by passage 47 controlled by valve 48 with the bustle pipe 18 of unit B.

In the operation of the apparatus with a two unit installation as shown, water-gas will be made in unit A by alternately blasting andsteaming the coke contained therein. In blasting the air is heated in stove M and then passes to the bustle pipe 18, through passage 39, valve 40 being open. It will be understood that during this blasting, valve 38, 34 and 23 will be closed.

The air passes through tuyeres 19 into the mass of carbonaceous residue or coke in the unit and the resultant combustion raises the temperature of the coke. The blast gases are lead out through passage 25, valve 26 being open and valve 21 closed, and pass to the carbureter K. From carbureter K they pass through passage 29, valve 30 being open, to steam-heater-L and thence through passage 43, valve 44 being open, to stove O. The valve 48 is closed and valve 46 is open and the gasespass outthrough passage 45.

At the expiration of the period of air blasting, valves 30, 40, 44 and 26 are closed and valves 21 and 34v opened. Steam is superheated in the heater L and passes through passage 32 to the bustle pipe 18 and thence through tuyeres 19 into the heated mass of coke in the unit, v

. The water-gas generated is conducted through passage 20 to the bustle pipe 18 of unit B and thence throughtuyeres 19 to the mass ofv coke inunit B. This mass of coke has been heated b blasting in a previous step of the cycle 0 operation as will appear hereafter, and the temperature of the gas is raised as it passes up through the mass of coke. It is thus highly heated as it reaches the layer of coal supported upon the coke and as it passes through this coal it carbonizes it, sweeping out the volatile matter and being enriched thereby.

With some fuels, there may be a tendency for thefuel to cake during the operation, the gas passing up adjacentv the walls .and through channels formed in the fuel. This will result in an unequal coking eifect throughout the fuel. In order to prevent this, and insure an equal treatment-throughout the body of fuel, it may be agitated by means of the poker shown, the poker being reciprocated or rotated by any suitable means.

The gas may be led off through passage 24" or may be led through passage 27, valve 28' being open, to the carbureter K where it may be further enriched by any suitable medium and then conducted by passage 31 to a gas container {not shown).

It will be understood thatif no enriching I medium is added in the carbureter, the pasthroughthis fuel.

- is then placed on the highly heated carbona-' sage of the gas therethrough will serve to fix the volatiles carried by the gas, these volatiles having beenswept out of-the fuel in the ceous residue remaining in unit A and the operation is reversed. Thecarbonaceous residuein unit B is now alternately blasted and steamed. The air is heated in stove 'O and the blast gases are passed from the steam-heater L to stove M. The water-gas produced is passed through passage 22 to bustle pipe 18 of unit A and into and up through the high ly heated coke in this unit and then'serves,

to remove the volatile contents of the fuel which has been placed in. the unit. 'f

In order toproperly co-ordinate the functioning of the .two units, an amount ofrcarbonaceous residue should; be consumed in producing water-gas ,in one unit, which amount equals the amount of such residue formed in the other unit,during the same period oftime. It may be' found desirable at times to add coketo one unit or fuel to the other at periods other than when theproce ss is reversed'in order to maintain-.theproper relation between the operation of the two units.

It is to be understood that the apparatus shown is for the purpose of illustration only since our process may be carried out by other apparatus. Further, the process may .becarfnfio ried out with such variations as come within the scope of the appended claims.

We claim:

1. The process of generating mixed water gas and coal gas by the use .of a plurality of similar units, which comprises alternately air blasting and steaming through carbonaceous residue in certain of said units, passing the-water-gas generated through heated carbonaceous residue in another unit where by its temperature is raised, passing the heated gas through a body of fresh coal in said latter unit, the sensible heat of the gas serving to largely remove the volatile contents of the coal thereby producingmixed water gas and coal gas, andagitating the mass of coal.

2. The process of generating mixed water gas and coal gas by the use of a plurality of similar units, which comprises alternately air blastingand steaming through carbonaceous residue in certain'of said units, passing the water-gas'generated through heated carbonaceous residue in another unit whereby its temperature is raised, and passing the heated gas through'a relatively thin layer of fresh coal supported on the heated carbonaceous residue in said latter unit, the sensible heat of the gas serving to largely remove the volatile contents of thecoal thereby p'roducingmixed water gas and coal gas, and

when said coal has been carbonized, finally air. blasting the carbonaceous residue which has been used in making gas in the first unit, adding a relatively thin layer of coal thereto and reversing the process, producing gas in the second unit in which the fuel has been carbonized and passing said gas through the carbonaceous residue which remains heated in the first unit and then through the added coal to remove the volatile contents of said 1 fuel and agitating the layer of coal.

Si ned at Chicago, Illinois, this 19th day of May, 1922.

CHARLES W. ANDREWS.

Si ed at Chicago, Illinois, this 18th day of ay, 1922.

HERMAN A. BRASSERT. 

